This invention relates to collagen encased food products such as sausages and encased cheeses. More particularly, the invention relates to such products wherein the collagen is coextruded with the food product to form a collagen coating thereon.
Traditionally, encased products such as sausages, have been prepared by extruding sausage meat into a prepared sausage casing.
Such casings have usually been prepared from sheep or pig intestines, regenerated cellulose, regenerated collagen and for certain products, made entirely from or including synthetic polymers or copolymers such as polyethylene, polyvinylidene chloride or nylon.
The only truly edible commercial food casings have been animal intestines and regenerated collagen.
Use of prepared food casings has had certain disadvantages. Such disadvantages have included the complexities involved in preparing the casings, packaging the casings, preserving the casings and utilizing the casings on stuffing machines. An especially troublesome problem has been utilization of the stuffing equipment since there is no way to continuously stuff a prepared food casing. Infinitely long casings do not exist and even if they did, there is no way to stuff such a casing since in all stuffing operations food must, in some way, pass through the interior of the casing, from one end to the other. As a result, stuffing of prepared food casings is, of necessity, a batch operation.
Additional disadvantages of using prepared shirred collagen casings are that the cross sectional area through which food may pass during stuffing is smaller when a shirred strand is used and the cost of manufacture of shirred strands is higher than would be desirable.
Attempts have been made to continuously prepare such encased food products by forming the casing as the product is made. Examples of such attempts have been to shape and seal a flat film into the form of a tube as the product is made and to coextrude products with the food which congeal or harden to form a casing.
An example of the latter is described in British Patent 1,232,801 where coextrusion of collagen with the food product is described. Such processes have not generally been successful with fresh sausage products since in the absence of high temperature processing or undesirable coagulation additives, the collagen coating is insufficiently stable to permit cooking of the sausage under usual conditions, e.g., by frying.
British Patent 1,232,801 does describe one example of collagen coated sausage, which does not appear to be heat treated, where an organic acid acidified collagen material is exposed to a setting bath containing ammonia. The exposure to ammonia unfortunately results in an undesirable odor and taste in the food product.